Founded in 1776, Washington County is one of 23 counties in the state of Maryland. Historically, Washington County was formed from part of Frederick County. The city of Hagerstown is the county seat. With FIPS code of 43, Washington County has a population of 154,937 and area of 468 square miles (1,212 km2).
List of all cities in Washington County, MD alphabetically
| City/Town | Postal Code | Area Code |
| Big Pool, MD | 21711 | 301/240/227 |
| Big Spring, MD | 21722 | 301/240/227 |
| Boonsboro, MD | 21713 | 301/240/227 |
| Brownsville, MD | 21715 | 301/240/227 |
| Cascade, MD | 21719 | 301/240/227 |
| Cavetown, MD | 21720 | 301/240/227 |
| Chewsville, MD | 21721 | 301/240/227 |
| Citicorp, MD | 21747 | 301/240/227 |
| 21748 | 301/240/227 | |
| Citicorp (BRM), MD | 21749 | 301/240/227 |
| Clear Spring, MD | 21722 | 301/240/227 |
| Fairplay, MD | 21733 | 301/240/227 |
| Fort Ritchie, MD | 21719 | 301/240/227 |
| Funkstown, MD | 21734 | 301/240/227 |
| Gapland, MD | 21779 | 301/240/227 |
| Hagerstown, MD | 21740 | 301/240/227 |
| 21741 | 301/240/227 | |
| 21742 | 301/240/227 | |
| 21746 | 301/240/227 | |
| 21747 | 301/240/227 | |
| 21748 | 301/240/227 | |
| 21749 | 301/240/227 | |
| Hancock, MD | 21750 | 301/240/227 |
| Highfield, MD | 21719 | 301/240/227 |
| Keedysville, MD | 21756 | 301/240/227 |
| Maryland Correctional System, MD | 21746 | 301/240/227 |
| Maugansville, MD | 21767 | 301/240/227 |
| Northern, MD | 21742 | 301/240/227 |
| Rohrersville, MD | 21779 | 301/240/227 |
| Saint James, MD | 21781 | 301/240/227 |
| Sharpsburg, MD | 21782 | 301/240/227 |
| Smithsburg, MD | 21783 | 301/240/227 |
| Williamsport, MD | 21795 | 301/240/227 |